Noble-Metal-Free WO3-Decorated Carbon Nanotubes with Strong W–C Bonds for Boosting an Electrocatalytic Glucose Oxidation Reaction

Electrocatalytic Upgrading of Plastic and Biomass-Derived Polyols to Formamide under Ambient Conditions

Electrocatalytic upgrading of wasted plastic and renewable biomass represents a sustainable method to produce chemicals but is limited to carbohydrates, leaving other value-added chemicals, such as organonitrogen compounds, being scarcely explored. Herein, we reported an electrocatalytic oxidation strategy to transform polyethylene terephthalate (PET) plastic-derived ethylene glycol (EG) and biomass-derived polyols into formamide, in the presence of ammonia (NH3) over a tungsten oxide (WO3) catalyst. Taking EG-to-formamide as an example, we achieved a high formamide productivity of 537.7 μmol cm-2 h-1 with FE of 43.2 % at a constant current of 100 mA cm-2 in a flow electrolyzer with 12-h test, representing a more advantageous performance compared with previous reports for formamide electrosynthesis. Mechanistic understanding revealed that the cleavage of the C-C bond in the EG was facilitated by nucleophilic attack of in situ formed nitrogen radicals from NH3, with resultant C-N bond construction and eventually formamide production. Furthermore, this strategy can be extended to transformation of PET bottle and a series of biomass-derived polyols with carbon number from three (glycerol) to six (glucose), producing formamide with high efficiencies. This work demonstrates a sustainable upgrading strategy of plastic and biomass that may have implications to more value-added chemicals production beyond carbohydrates.

Synthesis of a Ni(OH)2@Cu2Se hetero-nanocage by ion exchange for advanced glucose sensing in serum and beverages

Cu₂Se nanosheets were coated on the surface of Ni(OH)₂ nanocages (NCs) by ion exchange driven by selenium incorporation. The resulting Ni(OH)₂@Cu₂Se hollow heterostructures (Ni(OH)₂@Cu₂Se HHSs) showed high electrical conductivity and electrocatalytic activities derived from the synergistic effects of Ni/Cu phases. These structures enhanced glucose adsorption abilities, confirmed by density function theory (DFT) calculations, and the robustness of the integrated nano-electrocatalyst. Remarkably, Ni(OH)₂@Cu₂Se HHSs modified electrodes excited excellent glucose sensing behavior with a wide linear range (0.001-7.5 mM), a sensitivity up to 2420.4 Μa mM^-1 cm², a low limit of detection (LOD, 0.15 μM), and fast response (less 2 s). Furthermore, Ni(OH)₂@Cu₂Se HHSs competently analyzed glucose in serum and beverages with good recoveries ranging from 94.4 to 103.6%. Integrating copper selenide and Ni-based materials as 3D hollow heterostructures expands the selection of electrocatalysts for sensitive glucose detection in food and biological samples.

Selective photoelectrochemical oxidation of glucose to glucaric acid by single atom Pt decorated defective TiO2

Photoelectrochemical reaction is emerging as a powerful approach for biomass conversion. However, it has been rarely explored for glucose conversion into value-added chemicals. Here we develop a photoelectrochemical approach for selective oxidation of glucose to high value-added glucaric acid by using single-atom Pt anchored on defective TiO₂ nanorod arrays as photoanode. The defective structure induced by the oxygen vacancies can modulate the charge carrier dynamics and band structure, simultaneously. With optimized oxygen vacancies, the defective TiO₂ photoanode shows greatly improved charge separation and significantly enhanced selectivity and yield of C₆ products. By decorating single-atom Pt on the defective TiO₂ photoanode, selective oxidation of glucose to glucaric acid can be achieved. In this work, defective TiO₂ with single-atom Pt achieves a photocurrent density of 1.91 mA cm^-2 for glucose oxidation at 0.6 V versus reversible hydrogen electrode, leading to an 84.3 % yield of glucaric acid under simulated sunlight irradiation.

Fast and efficient electrocatalytic oxidation of glucose triggered by Cu2O-CuO nanoparticles supported on carbon nanotubes

Electrocatalytic glucose oxidation reaction (GOR) is the key to construct sophisticated devices for fast and accurately detecting trace glucose in blood and food. Herein, a noble-metal-free Cu/C-60 catalyst is fabricated by supporting Cu₂O-CuO nanoparticles on carbon nanotubes through a novel discharge process. For GOR, Cu/C-60 shows a sensitivity as high as 532 μA mM⁻¹ cm⁻², a detection limit as low as 1 μM and a steady-state response time of only 5.5 s. Moreover, Cu/C-60 has outstanding stability and anti-interference ability to impurities. The synergistic effect of Cu₂O-CuO could improve the adsorption and conversion of glucose, thus enhancing GOR performance. By using Cu/C-60, we fabricate a three-electrode chip. A portable and compact electrochemical system is constructed by connecting the three-electrode chip with Cu/C-60 to an integrated circuit board and a mobile phone for recording and displaying data. The portable and compact electrochemical system results in a GOR sensitivity of 501 μA mM⁻¹ cm⁻², which is close to the data measured on the bloated electrochemical workstation. The detection limit of the portable and compact electrochemical system in GOR is 50 μM. This is higher than those obtained on the bloated electrochemical workstation, but is much lower than the common blood glucose concentration of human body (>3 mM). This demonstrates the accuracy, reasonability and applicability of the portable and compact electrochemical system. The results of the present work are helpful for fabricating fast, efficient and portable devices for detecting trace amount of glucose in blood and food.